Since they are trying to fire the +Z axis motors and not getting good results even after using the spin up motors successfully my first thought would be something both those motors share that the others don’t.
Those two motors final valves might not be opening up the right way since they are getting the primary valves positive opening confirmation. They mentioned valve gaskets might not be good anymore and could have swelled to clog the valves.

Could they try the all the other motors just for a test to see if they those are good?

If so could the flip the craft end over and fire the -Z axis motors to see if those could give enough thrust to carry them into their desired position. They might not be as fast but maybe just maybe the craft could cost a bit longer to get there. During its coast in they could flip it back the correct direction and finish parking it.

This obviously depends on if they could keep radio contact flipping the other way around.